Drain pan



Got. 25, 1955 F. A. SCHUMACHER 2,721,451

DRAIN PAN Filed June 24, 1952 Irwverwtm Fr-emK ASchumacher His Attorneg.

United States Patent DRAIN PAN Frank A. Schumacher, Erie, Pa., assignorto General Electric Company, a corporation of New York Application June24, 1952, Serial N 0. 295,273

1 Claim. (Cl. 62-103) My invention relates to refrigerators and pertainsmore particularly to refrigerator defrosting apparatus.

Some refrigerators include means for automatically defrosting thosesurfaces in the food storage compartment thereof upon which frost formsand collects. Often such refrigerators also include means wherebymoisture resulting from a defrosting operation is evaporated into theatmosphere outside the food storage compartments and thereby disposedof. One arrangement for so disposing of the defrost moisture includes anauxiliary condenser located in the machinery compartment of therefrigerator and a rigid drain pan in heat exchange relationship withthe auxiliary condenser. The defrost moisture is directed into the drainpan from the defrosted surfaces and is evaporated by heat from theauxiliary condenser. The evaporation of defrost moisture from the drainpan is determined by the amount of heat transfer from the auxiliarycondenser to the drain pan. It has been recognized that by increasingthe heat transfer a smaller drain pan may be employed in thearrangement. Employment of a smaller drain pan is desirable from thestandpoints of economy in manufacture and conservation of space in themachinery compartment. Heretofore the thermal conductivity has beenincreased by bonding a pan to the auxiliary condenser. In such anarrangement, however, it proved difiicult to clean the pan, whichinvited neglect, resulting in pan corrosion and the presence ofmalodorous residues. Then a plate was secured to the condenser forremovably supporting the rigid pan and increasing the heat conductivityto the pan. Due to manufacturing difliculties in providing a flat bottompan and a flat plate, only three point contact resulted between the panbottom and the plate and insulative air gaps existed between the pan andthe plate.

The primary object of my invention is to provide in a refrigeratorincluding defrosting means an improved arrangement for evaporating andthereby disposing of moisture resulting from a defrosting operation.

Another object of my invention is to provide in a refrigerator includingdefrosting means and an auxiliary condenser, an improved defrostmoisture drain pan whereby high thermal conductivity between theauxiliary condenser and the drain pan and a resultant high defrostmoisture evaporation rate are insured.

Further objects and advantages of my invention will become apparent asthe following description proceeds and the features of novelty whichcharacterize my invention will be pointed out with particularity in theclaims annexed to and forming part of this specification.

In carrying out the objects of my invention, I provide a defrostmoisture receptacle having a flexible bottom and adapted to be supportedby a heated member. The flexible bottom conforms to the heated memberand thereby increases the thermal conductivity therebetween.

For a better understanding of my invention, reference may be had to theaccompanying drawing in which Fig. 1 is a fragmentary view of arefrigerator partly broken away to illustrate the preferred embodimentof my in- Patented Oct. 25, 1955 vention; Fig. 2 is an enlargedfragmentary sectional view of the preferred embodiment of my invention;Fig. 3 is an enlarged fragmentary sectional view illustrating analternative manner of supporting the defrost moisture receptacle; andFig. 4 is an enlarged fragmentary sectional view illustrating a secondembodiment of my invention.

In Fig. 1 is partially illustrated a refrigerator cabinet 1 including afood storage compartment shown in outline and indicated by 2, and amachinery compartment 3 disposed below the food storage compartment. Adoor 4 hingedly mounted on the refrigerator cabinet 1 is provided forclosing an access opening to the food storage compartment 2.

Located in the machinery compartment 3 is a refrigerating unit 5. Therefrigerating unit 5 is included in a refrigeration system provided forcooling the fresh food compartment. Also included in the refrigeratingsystem and located in the machinery compartment 3 is an auxiliarycondenser 6 which in operation assists the main condenser in the system(not shown) in dissipating heat absorbed by the system from the foodstorage compartment. During normal operation of the refrigerating systemthe absorption of heat from the food storage compartment 2 results inthe formation of frost therein. By means not shown the refrigerator isperiodically de- .frosted. The water or moisture resulting from thedefrosting operation is collected by suitable means and is conducted bya tube 7 to the machinery compartment 3.

As seen in Figs. 1 and 2 the above-mentioned auxiliary condenser 6 maycomprise a single conduit arranged in serpentine form and including aplurality of passes 8 disposed in a common horizontal plane. Secure tothe upper sides of the passes 8, as by welding, is a member or condenserplate 9, formed of steel or any similar heat conductive material. Inthis arrangement, the plate 9 is heated by the warm refrigerant flowingthrough the passes 8 of the auxiliary condenser 6. It is to beunderstood that means other than the auxiliary condenser may be employedto heat the member or plate 9. Supported by the'condenser plate 9 in aposition to receive the defrost moisture from the tube 7 is my improveddrain pan or receptacle 10. The embodiment of my invention illustratedin Figs. 1 and 2 is constructed wholly of a flexible heat conductivematerial, for example, a plastic material such as polystyrene. It is tobe understood of course that other materials can also be used dependingon flexibility, cost, durability, etc. The thickness of the material ofwhich the drain pan is formed and the configuration of the drain pan aresuch that the drain pan is structurally strong enough to hold water andnot collapse when picked up. Yet the pan material is flexible enough sothat the bottom indicated by 11 in Fig. 2 conforms to the top side ofthe condenser plate 9 when resting thereon. This insures a high rate ofthermal conductivity from the condenser plate 9 to the drain pan 10 andresults, therefore, in a high rate of evaporation of the defrostmoisture, indicated by 12 in Figs. 1 and 2, from the drain pan.

As the drain pan 10 becomes progressively more filled, the weight of themoisture 12 to be evaporated increases the conformance of the pan bottom11 to the plate 9 and increases the force with which the pan bottomengages the plate. Thus, the thermal conductivity and moistureevaporation rates increase with the rising of the level of the defrostmoisture 12 toward the point of overflow whereby the danger ofoverflowing is minimized. Similarly, if there should be any low spotswhere there is a greater tendency for water to collect, this greateramount of water also increases the contact and heat conduction betweenthe pan and the plate 9, thereby providing increased evaporation whereit is most needed.

As seen in Fig. 3, the drain pan 10 may be supported by the passes 8 ofthe condenser 6 instead of by the plate 9 secured to the passes. In suchan arrangement, the flexible bottom '11 conforms to and engages asubstantial surface area of each of the passes Sfin the manner shown insolid lines in Fig. 3. As the drain pan, becomes progressively morefilled, the Weight of the moisture 12 to be evaporated causes theportions of the bottom 11 of the pan between the passes 8 to movedownwardly toward the position shown in dash lines in Fig. 3. Thisincreases the total area of engagement between the pan bottom 11 and thecondenser passes 8, whereby the thermal conductivity and moistureevaporation rates are increased. It will be seen that as the drain panbecomes progressively more filled and closerto the point of overflow,the surface engagement between the bottom of the pan and the condenserpasses increases. Thus, the thermal conductivity and moistureevaporation rates I increase in proportion to increase in the amount ofdefrost moisture contained in the pan whereby the danger of overflowingis minimized.

In Fig. 4 is illustrated a modified form of my drain pan designated 13.The modified drain pan 13 comprises a rigid frame 14 formed of steel orthe like and a flexible bottom 15 which may be formed of the'samematerial as the first described embodiment lit. The bottom side of theframe 14 is formed to include an inwardly extending flange 16 to whichis suitably secured in a leakproof manner the edges of the flexiblebottom 15.

It will be seen that in this form of my invention the frame 14 may berelied upon for providing the necessary pan rigidity. Therefore, thebottom 15 may be thinner; and a more flexible material may be employedfor the bottom since the flexibility of the material selected will notbe at determining factor in the rigidity of the pan and the capabilityof the pan to hold Water and not collapse if lifted. With a thinner andmore flexible bottom, maximum conformance of the pan bottom to thecondenser plate 9 and a shorter heat path to the defrost moisture 12will be afforded. This will result in a more substan- I tial surfaceengagement between the pan bottom 15 and the condenser plate 9 wherebyhigher thermal conductivity and defrost moisture evaporation rates willbe obtained.

It is to be understood that in this form of the invention, too, theconformance of the pan bottom 15 to the plate 9 and the force Withwhichthe pan bottom engages the plate increases as the amount of moisturecontained by the drain pan increases for thereby minimizing the dangerof overflowing. It .is to be understood further that my'mo'dified drainpan 13 may also be supported by the passes 8 of the condenser 6insteadof by the plate 9 secured to the passes in the same manner andfor the same purposes described above with respect to the firstembodiment 10, and as illustrated in Fig. 3.

While specific embodiments of my invention have been shown anddescribed, it is not desired that my invention be limited to theparticular form shown and described and it is inte'nded by theappended-claims to cover all modifications'within the spirit and scopeof my invention.

What I claim as new and desire to be secured by Letters Patent of theUnited States is:

In a refrigerator, defrost moisture disposing means comprising; aserpentine condenser including a plurality of passes and a defrostmoisture evaporating receptacle removably supported by said condenserpasses, said receptacle including substantially, rigid sides and aflexible bottom, said flexible bottom engaging and conforming to saidcondenser passes whereby high thermal conductivity and defrost moistureevaporation rates are insured, the total surface engagement of saidflexible bottom with said condenser passes being proportionate to theamount of moisture contained in said receptacle.

Alsing July 25, 1939 Schlumbohn Sept. 26, 1939

